In a LED driver circuit, comprising a fly-back switching circuit or a fly back power converter, a transformer is typically used to transfer electrical energy from an input of the driver circuit to the LEDs via a secondary winding of the transformer. In addition a tertiary or auxiliary winding may be used to supply power to a controller (e.g. an integrated circuit) of the driver circuit, and/or for providing information regarding various voltages and transient signals of the switching waveforms within the power converter.
The use of such an auxiliary winding is disadvantageous as the auxiliary winding adds additional cost to the driver circuit and/or power converter. On the other hand, by removing the auxiliary winding, features such as the provision of a logic supply voltage for the controller of the driver circuit, the detection of freewheeling of the transformer and/or the measurement of various voltages may not be provided anymore.
The present document addresses the above mentioned technical problem. In particular, the present document describes a driver circuit and/or a power converter which is configured to provide any one or more of the above mentioned features without the need for an additional auxiliary winding. As a result of this, a cost efficient driver circuit and/or power converter, notably for SSL applications, is provided.
A further requirement regarding driver circuits and/or power converters for SSL devices is the compatibility with respect to dimmers, notably with respect to phase-cut dimmers. The driver circuits and/or power converters described in the present document may be configured and/or may be operated to be compatible with such dimmers. As such, cost efficient and dimmer compatible driver circuits for SSL devices may be provided.